Bottom Aft Rib Hole?

[RV7A]

I have the main spar, ribs, and aft spar matchdrilled and deburred. I'm ready to rivet it all together and then build the wing jigs for the skins.

I just noticed something though. Should the bottom hole in each rib be dimpled?



I'm sure the skin will be dimpled, which means the aft spar will get dimpled, which means that this hole in the rib should be dimpled, right?

I wish the manual would point out things like this. I almost started riveting the ribs to front and rear spars. If I would have thought of this question later, I would have to drill out all the rivets on the rear of the ribs to dimple these holes. (assuming the DO get dimpled)

[bullojm1]

I don't recall if this hole gets dimpled or not. Part of me thinks the rear spar gets countersunk. How thick is the rear spar? That would indicate if it could be countersunk.

[Joe Parish]

It does get dimpled on the 9 at least. I ended up dimpling both the rib hole and spar at the same time. Worked out ok for me.

[RV7A]

I've been looking at builders logs online to see if I could see if others had this hole dimpled. It looks like no one dimpled this hole before they riveted the aft ribs to the aft spar.

I'm pretty sure the aft spar gets dimpled and not riveted. But maybe others are also dimpling the rib and spar hole together too?

I e-mailed Van's also to see what they say. Hopefully tech support can get to my e-mail tomorrow (Monday).

[DaAV8R]

Some folks (like me ) overlooked this little detail and therefore dimpled the rear spar and rib in assembly.

I would drill both holes, debur and dimple prior to assembly. There isn't any reason not. While I am match drilling the whole process seems like a waste of time. If we were really correcting any misalignment during the match drilling process, we would end up with oblong holes. We are only removing a few thousandths of material. As that doesn't seem to happen during the match drilling process, I think we could bring them up to size, debut, dimple and move straight to assembly.


Robert

[RV7A]

Robert-that's what I always thought about matchdrilling too! I just don't want to be the first to try it!

Sounds good-I'll dimple the holes now and then rivet the rear spar together to the ribs.

Thanks everyone...

[Thermos]

I would drill both holes, debur and dimple prior to assembly.

+1. There's enough wiggle room on the fit of those tabs that you shouldn't have any problems drilling and dimpling these parts separately.

Dave

[BSwayze]

Not to change subjects in the middle of a thread, but I noticed you haven't primed those ribs yet. I'm sure you're on top of this, but I thought I'd mention it anyway... don't forget to get that done before you start riveting it all together.

[RV7A]

Thanks Bruce, I have decided not to prime this aircraft because even with no primer, it will outlive me.

I am however priming all surfaces that touch. So, I scuffed and primed the outside of all the ribs (and the rear spar.) I'm not sure if you can see that in the pic.

EDIT: I just looked at the pic and if you look close you can see that the front, rear, and outside edges (where it meets the skins) are primed with NAPA 7220 grey primer.

[BSwayze]

Okay, I do see that, now that you pointed it out. I missed it earlier!